High-frequency electrical oscillation apparatus



v L. R. McDONALD. HIGH FREQUENCY ELECTRICAL OSCILLATION APPARATUS.

APPLICATION FILED MAY I6, 1917.

1,389,255. Patented Aug. 30, 1921.

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UNITED STATES PATENT OFFICE.

' LESLIE B. MODONALD, OI MONTREAL, QUEBEC, CANADA, ASSIGNOR TO OIJELBX, OF MONTREAL, QUEBEC, CANADA.

WILLIAM J.

- mon-rnneumwcr anaemic. oscrnnarxon'arrmrus.

To all whom it may concern:

of which the following is a specification.

This invention relates to high-frequency electrical oscillation apparatus especially adapted for therapeutic use and for radio transmission, and more particularly the invention relates to means for generating high frequency oscillations and for impressing them from one circuit upon another Heretofore it has been the practice to employ either separate capacity elements or inductance elements or both such elements in circuits for generating high-frequency oscillations. These tuning elements not only involve additional cost of installation but they also introduce difliculties of maintenance inasmuch as they render the systems somewhat more complex and they also cause a considerable loss of energy.

It is the object of the present invention 1 to improve the efliciency and the degree of automaticregulation and the frequency of high-frequency oscillation systems, and to this end I have produced a system which is entirely free from separate capacity elements or other separate elements for tuning the system. Other objects of the invention will be apparent from the following description and the accompanying Fig. 5 is a diagrammatic plan view of the electrostaticelement shown in Fig. 4, also showing the preferred connections for this type of electrostatic element.

The particular embodiment of my inven ,tion shown in Fig." 1 comprises a supply circuit 1 which preferably leads to a source of alternating current of low frequency, a transformer T comprising a primary 2 and a secondary 3, a current varying element 4 Specification of Letters Patent.

Application filed Kay 16,

Patented Aug. 30, 1921. 1917. Serial no. 1ea,91 e.

which is preferably an electric arc connected in parallel with the secondary 3 of the transformer T, and an electrostatic element E. connecting the oscillation circuit 6 to the working circuit 7.

The electrostatic element E shown in Fig. 1 comprises a pluralit of spirally arranged bands 8, 9 and 11 0 copper or other suitable conducting material, these bands being separated by layers of mica 12 or of other. suitable insulating material. The .spiral bands 8 and 9 extend outwardly from the center in the same direction, namely, in a counter-clockwise direction, the two bands being entirely separate and being entirely insulated from each other. The bands 8 and 9 are respectively connected to the two leads of the oscillation circuit 6, and one band is preferably connected at its inner end to the one lead while the other band .is preferably connected at its other end to the other lead as shown in Fig. 1. The band 11 is connected, at its opposite ends to the working circuit 7, this band being arranged in spiral form and preferably being disposed outside and surrounding the bands 8 and 9.

The construction of the element E will be clear from an inspection of Fig. 3, which is a plan View of the element showing one end of the band 11 partially unwound. As indicated at 13 in Fig. 3, the leads extending to the inner ends of the bands are brought in at the sides of the element-between the layers of insulation 12.

The modified embodiment of the invention illustrated in Fig, 2 comprises a supply circuit 1, a transformer T having a primary 2 and a secondary 3, and an are 4 connected in parallel with the secondary 3 of the transformer across the oscillation circuit 6,. all as in Fig.1 1. However, the electrostatic element in Fi 2 differs from the electrostatic element shownin Fig. 1 in that it has two outer bands 14 and 16 instead of a single outer band 11, the outer end of. the band 14 being connected to the upper lead 7 of the working circuit and the inner end' of the band 16 being connected to thelower side of the working circuit ,7. The bands 14 and 16 are entirely separate and are entirely insulated from each other by means of the insulation 12. The inner bands 17 and 18 are connected to the circuit 6 in substantially the same manner as in Fig. v1. Instead of the type of construction of the Q i Y 1,889,256

electrostatic element illustrated in Figs. 1, 2 and 3, the type of construction shown in Figs. 4 and 5 ma be employed. In this construction the spiral conductors 21, one of which is shown in-elevation in Fig. 4, are disposed in parallel planes instead of in concentric relationship as in the type shown in Figs. 1, 2 and 3, the strips of conducting material being wound edgewise instead of fiatwise and layers of insulation '22 being. provided between the respective conductors 21. As shown in Fig. 5, the alternating conductors are preferably connected to the respective circuitsfi and 7, the first conductor being connected to one side of the oscilla-- tion circuit 6, the next conductor being connected to one side of the working clrcult 7, the next conductor being connected to the other side of the oscillation circuit,-and the next conductor being connected to the other side of the working circuit. The two leads from the oscillation circuit 6 are preferably connected to the inner and outer ends of the respective spiral conductors, as in Fig. 1, so as cumulatively to produce the magnetic field, and the leads from the working circuit 7 are preferably connected in similar manner so as to act cumulatively and, not differerentially. When employing more than four.

of the spiral conductors, a plurality of the conductors may be connected in parallel to each of the leads 6 and 7. The element illustrated in Figs. 4 and 5 is somewhat simpler to construct, inasmuch as no winding operation is involved, the conductors 21 being formed by a stamping operation or in any other suitable manner and being built up with layers of insulating material placed therebetween. However, the relation of the static field roduced by such a condenser to the magnetic produced by current flowing along t e spiral conductors is less effective than that of the electrostatic element illus trated in Figs. 1, 2 and 3.

In operating the system high-frequency oscillations are im ressed upon the working circuit 7 through t e medium of the electrostatic elementv by periodically varying the current in the oscillation circuit 6. As above stated the preferred means for producing the current variations comprises an are connected across the circuit in-the wellknown manner, although a spark-gap or other current varying means may be associated with the oscillation circuit in such manner as to produce the variations.

tively large capacity supplied to the oscillation circuit by the electrostatic elements is due in part to the open arrangement of the portions of the elements which are connected to the oscillation circuit andin art to the Earallcl disposition of the sai portions.

y varying the dimensions of the parts of the electrostatic elements and by varying their relative positions the capacity of the oscillation circuit and the degree of coupling between the oscillation and working circuits mav be controlled.

h'e arrangement of the portion of the electrostatic element E which is connected to the workin circuit whereby the working circuit is ren ered conductively discontinuous is of advantage under certain circumstances when it is desirable to provide a relatively large amount of capacity in this circuit. Moreover, the efliciency of the oscillation circuit appears to be increased by thls arrangement. he cardinal feature of the invention, however, lies in the described arrangement of the oscillation circuit side of the electrostatic element.

The principal advantages of my improved system are unprecedented efiiciency, automatic regulation, and exceedin ly high frequencies. Each of these a vantages is highly desirable and a system characterized by them all is uniquely adapted tomany uses, particularly in the art of electro therapy and radio-tele hony. The automatic regulation at high requencies is of particular significance in radio-telephony since a change in the resistance in the high-frequency side of the circuit has no appreciable effect upon the o ration of the system, whereas, in the or inary types of high frequency circuits, a change in the resistance of the working circuit necessitates an alteration of the impedance of the circuits in order to avoid a change in the current in the working circuit.

he advantages of my improved system I believe to be due in part to the elimination of all auxiliary capacity and inductance elements and appurtenances and in part to anovel phenomenon resulting from the combination of the capacity and inductance in a single element, whereby the static and magnetic fields are superposed, and particularly in the manner disclosed, whereby the fields are superposed in a per ndicular re-, lationship. The reason for t e increase'in eiiiciency resulting from the elimination of the auxiliary elements and the leads and other appurtenances incident to their use is apparent, but the reasons for the advantages flowing from the unique superposition of the static and magnetic fields are not so selfevident. However, I believe the latter to be substantially as follows, although it is to be understood that the theory which I advance is merely for the purpose of disclosing the in perpendicular relationship throughout the same region, namely, the region of the spiral conductors. The velocity ofpropagation of electromagnetic waves in an elastic medium is proportional to the quotient of the square root of the elasticity of the medium divided by the square rppi of the density of the medium (u= /e/d). The velocity of propagation of inductive waves depends upon the relation between the elasticity and the density of the medium through which the waves are propagated. The reciprocal 7c of the electric elasticity l/lc corresponds to the dielectric capacity, and the electrical density it corresponds to the magnetic permeability. The velocity of wave movement is therefore v= =1/ku.

Thus the elasticity and density of the medium constitute important factors in the movement of electrical waves and I believe the superposition of the static and magnetic fields in my improved electrostatic elements.

to cause the two fields so to react upon each other as to have the effect of changing the elasticity or density or both the elasticity and density of the medium throughout the region of the-superposed fields.

I am aware that so-called open-circuited transformers have been employed in various relations but I believe myself to be the first to employ an electrostatic element of the character described in a high-frequenc oscillation circuit to attain the objects ereinbefore set forth. I am also aware that an ordinary high-frequency transformer affords a small amount of capacity but the amount is inappreciable and I claim only the combination including an electrostatic element or an induction element having a greater degree of capacity than the ordi nary induction coupling.

I claim:

1. Electrical apparatus comprising a hi h frequenc oscillation circuit, and a wor ing circuit, the oscillation circuit having current var ing means therein and having bridged t ereacross means comprising large amounts of both capacity and inductance for supplying the necessary capacity to the 0S- cilla-tion circuit and for inducing oscillations into the working circuit.

2. Electrical apparatus comprising an oscillation circuit, a working circuit, means for supplying current to the oscillation circuit, an inductive coupling connecting the oscillation circuit with the working circuit, and current-varyingmeans k in the oscillation circuit for producing high frequency oscillations in the oscillation circuit, at least one of the windings of the inductive coupling being open so that the transformer affords a large proportion of the capacity of I the oscillation circuit.

3. Electrical apparatus comprising an'oscillation circuit, a working circuit, means for supplying current to the oscillation circu1t, .an inductive coupling connecting the oscillation circuit with the working circuit,

and current-varying means in the oscillation 1 circuit for producing high frequency oscillations in the oscillation circuit, the primary of the inductive coupling being open so that the coupling affords a large proportion of the capacity of the oscillation circuit.

4;. Electrical apparatus comprising an oscillation circuit, a working circuit, means for supplying current to the oscillation circuit, an inductive coupling connecting the oscillation circuit with the working circuit, and current-varying means in the' oscillation circuit for producing high frequency oscillations in the oscillation circuit, both the primary and secondary of the inductive coupling being open so that the coupling affords a large proportion of the capacity of the oscillation circuit.

5. Electrical apparatus comprising an oscillation circuit, a working circuit, impulse means for producing low frequency impulses of current in the oscillation circuit, an inductive coupling connecting the oscillation circuit with the working circuit, and an intermittent current-transmitting means bridging the oscillation circuit intermediate the impulse means and the inductive coupling so as to produce high frequency oscillations in the oscillation circuit, at least one side of the inductive coupling being open so that the coupling affords atleast a substantial portion of the capacity of the oscillation circuit.

6. Electrical apparatus comprising an oscillation circuit, a working circuit, means for supplying current to the oscillation circuit, an inductive coupling connecting the oscillation circuit with the working circuit,

and current-varying means in the'oscillation circuit for producing high-frequency LESLIE R. McDONALD. 

